System and method for non-invasive conversion of film cameras into digital cameras

ABSTRACT

A system and method for converting a film camera into a digital camera uses an electronic device placed in a space of the camera that normally contains film. The device includes an image sensing array arranged in optical communication with a lens of the camera when a shutter is open. An audio sensor is used to detect sounds within the camera, and an acoustic pattern recognizer with a built-in training mode is used to determine if the detected sounds correspond with the shutter operation. The image sensing array is switched into an image capture mode when the acoustic pattern recognizer determines that the shutter is being opened. When the shutter is opened, a read-out circuit captures multiple image frames from the image sensing array. An image processor associated with the image sensing array processes the captured images using advanced image processing algorithms.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S.application Ser. No. 11/727,465, filed Mar. 27, 2007, the entire contenteach of which are incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to digital photography, and more particularly tononinvasive systems and methods for converting film cameras into digitalcameras.

2. Description of the Related Art

Film cameras have been used for many years and have been made in avariety of sizes and formats. For example, typical film cameras havebeen available in film formats known in the industry as 35 mm, 110, 135,220, 660, and APS. All of these typical film cameras operate by placinga film canister or cartridge within a cavity of the camera, andsequentially positioning each frame of the film across an aperture inoptical communication with a lens when a shutter is opened. As thepictures are taken, the film is advanced by winding the film onto atake-up reel. After all of the pictures have been taken, the film iseither rewound off the take-up reel back into the film canister (in thecase of 35 mm film), or maintained within a take-up reel canister (inthe case of 110, 220 and 660 film). The film is then removed from thecamera and must be developed before the pictures are available.

Digital cameras have been developed more recently and are gaining inpopularity.

Digital cameras typically employ an electronic image sensing array, suchas a charge coupled device (CCD) or CMOS image sensing array, whichcommunicates with the lens of the camera. When a picture is taken, theshutter of the camera opens and exposes an image sensing array to light.The image sensing array captures the image, which is then retrieved fromthe array and stored in a memory. The camera can be coupled to acomputer or printer to download the images stored in the memory forimmediate on-screen viewing on the computer or printing on the printer.The camera can interface with a computer or printer using a cable, suchas a USB cable, or by using a memory device that can be removed from thecamera and plugged into a corresponding slot of the computer or printer.

Many photographers are switching from film cameras to digital cameras.However, these photographers often have valuable cameras, lenses,flashes, and other accessories for their film cameras that cannot beused with their new digital cameras.

A number of attempts have been made to provide film cameras with theability to take digital pictures. For example, U.S. Pat. Nos. 6,370,339and 6,351,282 both disclose systems for converting conventional filmcameras into digital cameras using an electronic apparatus that fits inthe area of the camera normally occupied by film. However, these priorattempts to convert film cameras into digital cameras have been met withonly limited success.

The present invention seeks to provide an improved system and method forconverting standard film cameras into digital cameras.

SUMMARY OF THE INVENTION

A system and method for converting a film camera into a digital camerauses an electronic device placed in a space of the camera that normallycontains film. The device includes an image sensing array arranged inoptical communication with a lens of the camera when a shutter is open.A read-out circuit is coupled to the image sensing array, and a memoryis coupled to the read-out circuit for storing a digital pictureobtained from the image sensing array. An audio sensor is included inthe electronic device to detect sounds within the camera. An acousticpattern recognizer connected to the audio sensor determines if thedetected sounds correspond with the shutter operation of the camera. Theacoustic pattern recognizer has a training mode that can be used afterthe device is loaded into the camera to develop a set of acousticpatterns specific to the camera in which the device is loaded. Thetraining mode uses signals received from the audio sensor and the imagesensing array to determine the particular acoustic pattern that precedesthe shutter opening. Once the training mode is completed, the imagesensing array will be switched from a low power listening mode into animage capture mode when the acoustic pattern recognizer determines thatthe shutter is about to be opened.

When the shutter is opened, the read-out circuit operates to capturemultiple image frames from the image sensing array. An image processorassociated with the image sensing array processes the captured images todetermine when to end the image capturing process and to identify andkeep only valid images captured during the shutter opening. The imageprocessor also uses advanced image processing algorithms to obtain oneor more high quality images from the multiple captured images. Forexample, the image processor can apply a super-resolution imagingalgorithm to synthesize a high-resolution image from a sequence oflow-resolution images captured during the shutter opening. The imageprocessor can also use an image enhancement algorithm to enhance animage captured during the shutter opening. The image processor can alsobe used to compress and store the captured images.

According to one aspect, the present invention provides a system forconverting a film camera into a digital camera, comprising: an imagesensing array; a read-out circuit coupled to the image sensing array; amemory coupled to the read-out circuit for storing a digital picturederived from an image read-out from the image sensing array; an audiosensor for detecting sounds within the camera; and an acoustic patternrecognizer that compares signals received from the audio sensor todetermine if the signals correspond with acoustic patterns associatedwith shutter operation, the acoustic pattern recognizer having atraining mode that can be used to develop a set of acoustic patternsassociated with shutter operation based on signals from the audio sensorduring the training mode; and the image sensing array having a low powerlistening mode and an image capture mode and being switchable from thelow power listening mode into the image capture mode when the patternrecognizer recognizes an acoustic pattern associated with shutteroperation.

According to another aspect, the present invention provides a system forconverting a film camera into a digital camera, comprising: an imagesensing array; a read-out circuit coupled to the image sensing array;and a memory coupled to the read-out circuit for storing a digitalpicture derived from an image read-out from the image sensing array; theread-out circuit being operable to capture more than one image framefrom the image sensing array during a single opening of a shutter of thefilm camera.

According to another aspect, the present invention provides a method oftaking a digital picture with a film camera, comprising: loading anelectronic device comprising a memory unit and an image processor into aspace vacated in the absence of film in the camera, and placing an imagesensing array in optical communication with a lens of the camera when ashutter is open; detecting sounds within the camera using an audiosensor; and developing a set of acoustic patterns associated withshutter operation based on signals from the audio sensor and the imagesensing array during a training mode after the electronic device isloaded into the film camera.

The present invention can be embodied in various forms, includingbusiness processes, computer implemented methods, computer programproducts, computer systems and networks, user interfaces, applicationprogramming interfaces, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other more detailed and specific features of the presentinvention are more fully disclosed in the following specification,reference being had to the accompanying drawings, in which:

FIG. 1 is a rear perspective illustration of an electronic device of thepresent invention being inserted into a conventional film camera;

FIG. 2 is a front perspective illustration of the electronic device;

FIG. 3 is a block diagram illustrating the functional elements of theelectronic device of the present invention;

FIG. 4 is a flowchart illustrating the operation of the electronicdevice, including a training mode for developing a set of acousticpatterns associated with the shutter operation; and

FIG. 5 is another flowchart illustrating the operation of the imageprocessor of the electronic device.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, for purposes of explanation, numerousdetails are set forth, such as flowcharts and system configurations, inorder to provide an understanding of one or more embodiments of thepresent invention. However, it is and will be apparent to one skilled inthe art that these specific details are not required in order topractice the present invention.

A conventional camera 10 is shown in FIG. 1 with its back cover 11 open.The camera 10 has a body 12, a lens 13, and a shutter button 14. Animage focal plane area 15 is provided inside the camera where the lens13 produces a focused image. Various parts and details of the camera 10will not be described in detail herein and are well known to thoseskilled in the art.

An electronic device 20 according to the present invention is also shownin FIG. 1, and in more detail in FIG. 2. The electronic device 20 ispackaged in a shape and size that allow it to fit into the space 21 ofthe camera 10 normally used to hold the film canister/cartridge andfilm. The electronic device 20 shown in FIG. 1 is shaped for a 35 mmcamera, but the electronic device 20 can be provided in other shapes andsizes to fit into other common types of cameras, such as 110, 135, 220,APS, and so forth.

The electronic device 20 has an image sensor array 22 positioned on itsfront side at a location that corresponds with the image focal planearea 15 of the camera 10 when the device 20 is loaded into the camera10. The image sensor array 22 is thus positioned at the same locationthat a frame of the film would normally be positioned to be exposed toan image. An audio sensor 23 is provided for detecting camera noisesduring operation. The audio sensor 23 is a sensitive microphonecalibrated to pick up all noises from the camera body 12 and operates asthe noninvasive interface between the camera body 12 and the electronicdevice 20. The device 20 also includes a housing 24 in which otherelectronic circuitry is contained, as further described below.

The functional elements of the electronic device 20 are illustrated inthe block diagram of FIG. 3. The image sensing array 22 is coupled to aread-out circuit 25, which in turn is coupled to an image processor 26.The device 20 also includes a rechargeable power cell 27 for supplyingpower to the processor 26 and the other components, and a non-volatileerasable memory 28 in which the processed images are stored. Aninterface 29 is provided for transferring images from the device 20 toan external computer or printer. For example, the interface 29 can be aUSB port or a wireless interface, such as a radio frequency transmitter.Alternatively, the non-volatile erasable memory 28 may be a removableflash memory device including but not necessarily limited to MemoryStick™ as provided by Sony Corporation, Tokyo Japan, SD memory cards,and others.

As mentioned above, the electronic device 20 includes an audio sensor 23for detecting the sounds of the camera 10 during operation. The audiosensor 23 is connected to an acoustic pattern recognizer 30 in theelectronic device 20. The acoustic pattern recognizer 30 is alsoconnected to the image processor 26, and is operable to match theacoustic patterns received from the audio sensor 23 with the timing ofthe shutter opening. As a result, it is possible to develop a set ofacoustic patterns that accurately predict (milliseconds in advance) theopening of the shutter of the camera 10 to take a picture. This allowsthe electronic device 20 to stay in a low power listening mode untiljust before the shutter opens to capture an image. When the acousticpattern recognizer 30 determines that the shutter is about to open, itcauses the processor 26 to enter an image capture mode that hasrelatively higher power consumption. This reduces the power demandduring time periods when the device 20 is not in use, and alsoeliminates unnecessary image capturing when the camera shutter isclosed.

The electronic device 20 includes a training mode to develop a set ofacoustic patterns that match the shutter operation of the particularcamera 10 in which the device 20 is to be used. The training mode allowsthe device 20 to be easily adapted for use in almost any film camerawithout knowing in advance the particular acoustic pattern associatedwith the camera's shutter operation. Thus, the electronic device 20 doesnot need to be manufactured or programmed differently for each specificcamera model. The training mode allows for differences between differentcamera models and even differences among the same camera model, whichmight be caused by different use patterns, manufacturing tolerances, andso forth. By incorporating the training mode in the electronic device 20of the present invention, it is possible to adapt the device 20 for usewith any particular camera designed to use the same size film.

The process of converting a film camera 10 into a digital camera usingthe electronic device 20 of the present invention will now be explainedwith reference to FIG. 4. In step 101, the electronic device 20 isloaded into the camera 10, and then the back 11 of the camera 10 isclosed in step 102. The device 20 then automatically or manually entersthe training mode in step 103 to develop a set of acoustic patterns forthe specific camera in which it is placed. In one exemplary embodiment,the training mode is entered automatically each time the device 20 isinserted in a camera 10 (e.g., using pressure switches on the device 20that detect the closing of the camera back 11).

The training mode starts in step 104 by powering up the processor 26 andthe other circuits of the device 20. As indicated in step 105, the audiosensor 23 is used during the training mode to listen for and detectsounds within the camera 10. The user is instructed to press the shutterbutton 14 of the camera 10 at least once during the training mode tocause the shutter to open as if taking a picture. The shutter button 14can be pressed multiple times during the training mode to allow theacoustic pattern recognizer 30 to fine tune its set of recognizedacoustic patterns. The opening of the shutter and, more importantly, themovement of various other parts of the camera 10 in connection withopening the shutter, create a unique acoustic pattern within the camera10. The acoustic pattern is detected by the audio sensor 23 and fed tothe acoustic pattern recognizer 30. In step 106, data from the imagesensing array 22 or a separate light sensor is detected and then used instep 107 to match the timing of the shutter opening with the detectedacoustic pattern. The acoustic pattern and its precise timing correlatedto the shutter opening, the start frame, the end frame, the backgroundnoise level, the signal-to-noise ratio, and so forth, are determined instep 107 and then stored in the acoustic pattern recognizer 30 in step108. The training mode is then complete and the acoustic patternrecognizer 30 will be able to accurately predict the start and end ofthe shutter opening for that particular camera 10.

The acoustic pattern recognizer 30 can have some preloaded patterns fromother cameras so that the electronic device 20 has a model and generalidea what to expect from the user's camera 10. The preloaded patternswill be compared with the acoustic patterns detected during the trainingmode to develop a more precise acoustic pattern associated with theshutter operation of the user's camera 10. The acoustic patternrecognizer 30 can also be set to fine tune its recognized patterns everytime the user presses the shutter button 14 to continue to improve itsrecognition performance specific to the camera in which it is loaded.

After the training mode is complete, or if the training mode is bypassed(e.g., the shutter is not activated within a predetermined time period),the device 20 enters a low power listening mode in step 109. In thelistening mode, the audio sensor remains in a low power listening state110 until camera operation sounds are detected in step 111. When cameraoperation sounds are detected, the acoustic pattern recognizer 30compares the detected acoustic pattern in step 112 with the knownacoustic pattern(s) stored during the training mode. If the detectedacoustic pattern is not recognized, the process remains in the low powerlistening state 110 and continues to listen for camera operation sounds.A threshold sound level can also be used so that the circuits of theacoustic pattern recognizer 30 are kept in a low power state until thenoise within the camera 10 exceeds a predetermined threshold, at whichtime the circuit of the acoustic pattern recognizer 30 wakes up todetermine whether the detected acoustic pattern is recognized as apattern associated with the shutter operation.

If the acoustic pattern recognizer 30 determines in step 112 that theacoustic pattern matches the known acoustic pattern of the camera 10just before the shutter opens, then a signal is sent in step 113 topower-up the processor 26, the image read-out circuit 25 and the imagesensing array 22 into the high power image capture mode. In step 114,the processor 26 controls the image read-out circuit 25 to acquiremultiple image frames from the image sensing array 22 during a singleopening of the camera shutter. For example, a sequence of five imageframes can be captured during a single shutter opening event. Themultiple image frames are then processed in step 115 and stored in thememory 28 of the device using advanced image processing algorithms, asfurther explained below. By accurately predicting in advance when theshutter of the film camera 10 will be opened, the present inventionallows a low power energy-saving mode to be used while still ensuringthat multiple images can be captured from a single shutter opening. Theprocess continues to cycle through these steps 109-115 until the memory28 is full or the camera back 11 is opened to remove the device 20.

It should also be noted that acoustic pattern adaptation may be ongoing.For example, every time an acoustic pattern is successfully recognizedthe existing acoustic pattern may be modified so that adaptation cantake place. In this way, the stored acoustic pattern and correspondingrecognition can continuously improve and also evolve where acousticchanges that might occur after long periods of time (e.g., due to wearand tear of shutter internal parts and the like). This adaptation mayoccur based upon each acoustic pattern recognition event, based upon theresults of several stored acoustic pattern recognition events, or basedupon a training review prompted at regular periods, etc.

The image processor 26 of the electronic device 20 performs allnecessary image processing functions on the sequence of images capturedby the image sensing array 22. The image processor 26 is programmed withmotion estimation algorithms and advanced image processing algorithms toimprove and enhance the quality of the images captured by the device 20.An exemplary set of such advanced image processing algorithms isillustrated in FIG. 5.

As illustrated in FIG. 5, the image processor 26 receives multiple imageframes from the read-out circuit 25 in step 120. The image processor canbe programmed to cause the read-out circuit 25 to end the imagecapturing process in step 121 after a predetermined number of imageframes are captured, or once the image data indicates the shutter hasclosed. The image processing algorithms are then used by the imageprocessor 26 in step 122 to determine which of the image frames capturedfor each shutter opening event are similar (“valid”) and to reject therest as being either too early or too late relative to the shutteropening (typically, none of the frames will be identical because of thecamera movement or the movement of the subject).

The image processor 26 then applies a super-resolution imaging algorithmin step 123 to synthesize a high-resolution image from a sequence oflow-resolution images captured during the shutter opening. For example,the electronic device 20 might use a 1-Megapixel camera sensor, butbecause of the super-resolution imaging it will produce a 5-Megapixelimage from a sequence of lower resolution images. Conventionalsuper-resolution processing techniques may be implemented by the imageprocessor to accommodate this functionality. The image processoraccesses a set of images corresponding to the same image capture sessionand performs any aliasing and pixel shifting to accommodate merging ofthe images to the high-resolution image. If desired, where motionestimation functionality is incorporated, the determination of motionmay be correlated to the capture of images and that information isincorporated into the super-resolution imaging algorithm in order toaccommodate for motion that may have occurred during image capture.

In addition to, or instead of, the super-resolution imaging algorithm,the image processor also includes an image enhancement algorithm, asdepicted in step 124. The image enhancement algorithm can be used toenhance a relatively low quality image for better resolution and picturequality. Various image enhancement algorithms may be implemented,including but not limited to those that implement edge detection andprocessing, shape recognition, contrast factors, color factors, andothers.

Once the advanced image processing algorithms complete their imageprocessing in steps 121-124, then the processed image is compressed andstored in the memory 28 of the electronic device 20 in step 125. Theimages stored in the memory 28 can be transferred to an externalcomputer using suitable peripherals, such as a communication port (e.g.,USB port) on the electronic device, a radio frequency communicationdevice, or other known data transfer techniques and devices.

The electronic device 20 of the present invention is camera independentand can be manufactured in the form factor of all popular film formatsand cameras. Since the device 20 develops its own set of recognizedacoustic patterns in whatever camera it is placed, its correlationbetween the camera's shutter operation and the image capturing mode ishighly accurate and readily adaptable to any camera in which the deviceis loaded.

When the memory 28 is full or the battery is low, the device 20 can beequipped to emit audible warnings to the user. In another embodiment,warning and status messages can be displayed on a wireless control panelaffixed to the outside of the camera body 12.

The system and method according to the present invention provide anon-invasive way of transitioning from film to digital photography,while keeping and using existing photographic gear. The transition usingthe present invention is simple and does not risk damage to the filmcamera in case the user desires to convert the camera back to film use.The user does not need to learn any complicated procedures for using anew digital camera. The technique is non-invasive so no modifications tothe existing film camera are needed. The cost of making the conversionis low because all existing photography gear can be reused. The existingcamera can continue to be used for exposure and focus control in anormal manner.

In the description herein, numerous specific details are provided, suchas examples of components and/or methods, to provide a thoroughunderstanding of embodiments of the present invention. One skilled inthe relevant art will recognize, however, that an embodiment of theinvention can be practiced without one or more of the specific details,or with other apparatus, systems, assemblies, methods, components,materials, parts, and/or the like. In other instances, well-knownstructures, materials, or operations are not specifically illustrated ordescribed in detail to avoid obscuring aspects of embodiments of thepresent invention.

The embodiments of the present invention produce and provide systems andmethods for noninvasive conversion of film cameras into digital cameras.Although the present invention has been described in considerable detailwith reference to certain embodiments thereof, the invention may bevariously embodied without departing from the spirit or scope of theinvention. Therefore, the following claims should not be limited to thedescription of the embodiments contained herein in any way.

1. A system for converting a film camera into a digital camera,comprising: an image sensing array; a read-out circuit coupled to theimage sensing array, an image processor associated with said imagesensing array and said read-out circuit, said image processor isoperable to end an image capturing process; and a memory coupled to theread-out circuit for storing a digital picture derived from an imageread-out from the image sensing array; said read-out circuit beingoperable to capture more than one image frame from said image sensingarray during a single opening of a shutter of the film camera.
 2. Thesystem according to claim 1, wherein said image processor is operable toidentify and keep only valid images captured during the shutter opening.3. The system according to claim 1, wherein said image processor isoperable to enhance an image captured during the shutter opening.
 4. Thesystem according to claim 1, wherein said image processor is operable tocompress and store an image captured during the shutter opening.